Fellion functioned as an agent of enforcement for the Black Sun crime organization operating on Brentaal in the time period preceding the demise of Prince Xizor.
The origins of Fellion's life remain largely unknown; however, it is documented that she initially acquired her military skills through service within a privately-owned militia located in the Kathol Outback. Subsequently, she journeyed Coreward and became affiliated with Black Sun on Brentaal, a significant trade center. Within the organization, she operated as a clandestine enforcer, responsible for the elimination of targets that presented significant challenges due to their protection or other complexities. An example of such a mission took place in the years leading up to the Galactic Civil War, when Black Sun attempted to infiltrate mainstream business on Brentaal through the hostile takeover of House Okeefe. The initial attempt, conducted by standard thugs, failed when a member of House Okeefe hired independent contractors to deal with the 'petty criminals'. Fellion received the order to eliminate the interlopers before they could hinder Black Sun's activities on Brentaal. Her initial attempt to assassinate them was unsuccessful, which revealed her involvement. The freelancers, now aware of their enemy's identity, launched a bold assault on the Black Sun base located at the Alfex Cargo Stacks. Fellion perished during this exchange of gunfire.
Fellion possessed a naturally unassuming and meek appearance. This ordinary look proved to be more effective than any armor. In combat situations, she generally avoided using advanced gadgets, preferring to utilize her martial arts skills and a variety of blaster weaponry to accomplish her objectives.